Pilot skills are hardcoded, locked in C++. That isn't to say you can't make your own, it just means we have no existing examples to draw from. The existing pilot mod was made completely from scratch. You can put something like this anywhere to check a mech's pilot and do something if the pilot's name matches your custom pilot:

if _G[MyPawnName:GetPersonality()] == "MyPilotName" then [do some cool stuff]end